The ZIP file format is a popular and convenient tool for combing multiple files into a single compressed archive suitable for sharing with others or simply archiving old files for safekeeping. ZIP files can be encrypted with a password for privacy and security, but it means that the files inside the archive are inaccessible if the password is ever lost or forgotten. Fortunately, there are ways to recover the password and FCrackZip is a free open source password recovery tool for Linux that is fast and capable of performing both dictionary and brute-force attacks against password-protected ZIP files.

fcrackzip is a fast password cracker partly written in assembler. fcrackzip is able to crack password protected zip files with brute force or dictionary based attacks, optionally testing with unzip its results. It can also crack cpmask'ed images.

Install fcrackzip in Ubuntu

sudo apt-get install fcrackzip

Using fcrackzip:
First let's create an simple password protected zip file, open up your terminal and type following command:

zip --encrypt -r test test/

Let's provide the password "ubuntu" for this zip file

Now, run the following fcrackzip command to break it and in the terminal console you should see something similar to this ....

fcrackzip -c a -p aaaaaa test.zip

Options:
a include all lower-case characters [a-z]
A include all upper-case characters [A-Z]
1 include the digits [0-9]
! include [!:$%&/()=?[]+*~#]
: the following characters up to the end of the specification string are included in the character set.

This way you can include any character except binary, there are many more option you can pass to fcrackzip, please check the man pages for more details.

checks the encrypted files in sample.zip for all lower-case 6 character passwords as shown in the picture below ...